Some work involves the need to hoist heavy loads to a very great height and in locations which are very difficult to reach. This is the case, for example, in the erection of metal pylons for lines of high or very high voltage. These pylons are installed in regions to which only cross-country cranes can gain access. However cranes of this type which are at present on the market have characteristics which do not allow them to carry out this kind of work. In particular, their maximum jib length is insufficient and their moment of stability is too low.